I should've mentioned that myself, a proper warmup is important. Don't just spend 10 seconds stretching a couple muscles, you gotta put some time out so that you can do them properly.

I found that several minutes of cool down exercises are great just for recovering from the workout. Just catching your wind and stretching your muscles in the end can make all the difference.

Besides that it's what comes with boxing, you're always going to be sore, aching or hurt. It's a real fighter that keeps going.